Complete adverse effect profile including incidence rates and management
Important Safety Information
This is not a complete list of all possible side effects. Contact your healthcare provider if you experience any unexpected symptoms. For serious or life-threatening side effects, seek emergency medical attention immediately.
ADVERSE REACTIONS Ibutilide fumarate injection was generally well tolerated in clinical trials.
Of the 586 patients with atrial fibrillation or atrial flutter who received ibutilide fumarate in phase II/III studies, 149 (25%) reported medical events related to the cardiovascular system, including sustained polymorphic ventricular tachycardia (1.7%) and nonsustained polymorphic ventricular tachycardia (2.7%).
Other clinically important adverse events with an uncertain relationship to ibutilide fumarate include the following (0.2% represents one patient): sustained monomorphic ventricular tachycardia (0.2%), nonsustained monomorphic ventricular tachycardia (4.9%), AV block (1.5%), bundle branch block (1.9%), ventricular extrasystoles (5.1%), supraventricular extrasystoles (0.9%), hypotension/postural hypotension (2%), bradycardia/sinus bradycardia (1.2%), nodal arrhythmia (0.7%), congestive heart failure (0.5%), tachycardia/sinus tachycardia/supraventricular tachycardia (2.7%), idioventricular rhythm (0.2%), syncope (0.3%), and renal failure (0.3%).
The incidence of these events, except for syncope, was greater in the group treated with ibutilide fumarate than in the placebo group.
Another adverse reaction that may be associated with the administration of ibutilide fumarate was nausea, which occurred with a frequency greater than 1% more in ibutilide-treated patients than those treated with placebo.
The medical events reported for more than 1% of the placebo- and ibutilide-treated patients are shown in the following Table.
Treatment-Emergent Medical Events With Frequency of More Than 1% and Higher Than That of Placebo Event Placebo N=127 All Ibutilide N=586 Patients Patients n % n % CARDIOVASCULAR Ventricular extrasystoles 1 0.8 30 5.1 Nonsustained monomorphic VT 1 0.8 29 4.9 Nonsustained polymorphic VT — — 16 2.7 Hypotension 2 1.6 12 2.0 Bundle branch block — — 11 1.9 Sustained polymorphic VT — — 10 1.7 AV block 1 0.8 9 1.5 Hypertension — — 7 1.2 QT segment prolonged — — 7 1.2 Bradycardia 1 0.8 7 1.2 Palpitation 1 0.8 6 1.0 Tachycardia 1 0.8 16 2.7 GASTROINTESTINAL Nausea 1 0.8 11 1.9 CENTRAL NERVOUS SYSTEM Headache 4 3.1 21 3.6 In the post-cardiac surgery study (see CLINICAL STUDIES ), similar types of medical events were reported.
In the 1 mg ibutilide fumarate treatment group (N=70), 2 patients (2.9%) developed sustained polymorphic ventricular tachycardia and 2 other patients (2.9%) developed nonsustained polymorphic ventricular tachycardia.
Polymorphic ventricular tachycardia was not reported in the 73 patients in the 0.5 mg dose group or in the 75 patients in the 0.25 mg dose group.
WARNINGS Proarrhythmia Like other antiarrhythmic agents, ibutilide fumarate injection can induce or worsen ventricular arrhythmias in some patients.
This may have potentially fatal consequences.
Torsades de pointes, a polymorphic ventricular tachycardia that develops in the setting of a prolonged QT interval, may occur because of the effect ibutilide fumarate has on cardiac repolarization, but ibutilide fumarate can also cause polymorphic VT in the absence of excessive prolongation of the QT interval.
In general, with drugs that prolong the QT interval, the risk of torsades de pointes is thought to increase progressively as the QT interval is prolonged and may be worsened with bradycardia, a varying heart rate, and hypokalemia.
In clinical trials conducted in patients with atrial fibrillation and atrial flutter, those with QTc intervals greater than 440 msec were not usually allowed to participate, and serum potassium had to be above 4 mEq/L.
Like all medications, Ibutilide Fumarate can cause side effects. However, not everyone who takes this medication will experience them. Many side effects are dose-dependent and may improve as your body adjusts to the medication. Others may require dose adjustment or medical attention.
Contact your healthcare provider promptly if you experience:
Seek immediate emergency medical care if you experience signs of: